Re: min() and NaN

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Well, my 2 cents is that though we consider NULL when ordering via ORDER
> > BY, we ignore it in MAX because it really isn't a value, and NaN seems
> > to be similar to NULL.
>
> Good idea, but I don't think we can get away with it. The spec says
> that MAX/MIN have to be consistent with the comparison operators (and
> therefore with ORDER BY):
>
> iii) If MAX or MIN is specified, then the result is respec-
> tively the maximum or minimum value in TXA. These results
> are determined using the comparison rules specified in
> Subclause 8.2, "<comparison predicate>".
>
> NULL can be special, because it acts specially in comparisons anyway.
> But NaN is just a value of the datatype.
>
> I'd be willing to go against the spec if I thought that having
> ignore-NaNs behavior was sufficiently important, but I don't think it's
> important enough to disregard the spec...

Yep.

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